520 



Dr. F. W. Pavy on the 



[Apr. 24 



V. " Further Researches on the Physiology of Sugar in relation 

 to the Blood." By F. W. Pavy, M.D., F.R.S. Received 

 April 3, 1879. 



The results brought forward in this communication are supplemen- 

 tary to those published in the " Proceedings of the Royal Society " for 

 June, 1877 (vol. xxvi, pp. 314, 346). 



The first of these communications was devoted to the consideration 

 of the quantitative determination of sugar for physiological purposes. 

 Some important physiological conclusions had been drawn by Bernard 

 from the results obtained through a modified method introduced by 

 him of employing Fehling's solution. I pointed out the manner in 

 which 1 considered the process in question to be open to fallacy, and 

 showed that the results yielded by it differed to a marked extent from 

 those yielded by a gravimetric method, which I described, of using the 

 copper test, 



I have since continued my investigations, and have now results to 

 bring forward obtained by another process, which I described in a com- 

 munication read at the Royal Society, January 16, 1879, and published 

 in the " Proceedings," vol. xxviii, p. 260. This process does not differ 

 in principle of action from Bernard's, and if there were no fallacy in 

 either case involved, the results yielded by the two should agree. In 

 both the reduction of the oxide of copper is made to occur without 

 the precipitation of the reduced oxide, so that the change to be watched 

 in the action of the test is a progressive decoloration, unobscured by 

 the presence of any deposit. In Bernard's process this result is 

 brought about by the action of potash in a concentrated form upon the 

 organic matter incidentally present in the product prepared for exami- 

 nation, and the agency in force is, according to the view I have 

 expressed, the development of ammonia. In my own process, for 

 particulars regarding which I must refer to the published communica- 

 tion in the " Proceedings," ammonia is added to the test, and no fixed 

 alkali employed beyond that present in Fehling's solution. 



By means of this new process an opportunity is afforded of ascer- 

 taining on which side the fault lies in the disagreement between the 

 results obtained by Bernard's and the gravimetric method. 



The accompanying table contains the results given by the applica- 

 tion of the three processes to six specimens of blood. 



The figures in the first two columns are derived from the analyses 

 respectively conducted with the use of potash (Bernard's plan) and 

 ammonia, and with the adoption of Bernard's proposition that the 

 liquid obtained from equal weights of blood and sulphate of soda 

 measures, in cub. centims., four-fifths of the total weight in grammes 

 of the sulphate of soda and blood taken. 



